Specify custom styles for individual blocks (perhaps using taxonomy?)

My basic question is this: Is there any way to categorize blocks using the taxonomy module? Let me give you some context so you'll see why I want to do this and maybe someone can come up with a better idea than what I'm thinking.

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The owner of the site really likes being able to rearrange the six boxes on the front page. I'm using blocks for those boxes and styling them one at a time using CSS (in other words, I have separate CSS rules for .block-block-1, .block-block-2, etc.). Some of them have dotted outlines and a little pair of scissors, and are thus intended to be coupons. Some are simply a solid border and are used as shout boxes. There are six different colors he can choose from. So, he already has 12 different blocks that he can swap in and out of the mix.

Now he's asking me to add another layer of complexity: different sized boxes. He wants some boxes that will extend across two or three spaces, some that will extend up and down two spaces, and even a giant two by two block that will take up four spaces. I know exactly how to do all of this with CSS, but I'm loathing the idea of creating wide boxes, tall boxes, and giant boxes in all six colors and two border styles (36 different blocks, altogether). I'm thinking there has to be a better to apply each attribute separately.

Enter taxonomy terms. I'm thinking I should be able to easily create a taxonomy with six options for colors, a taxonomy with two options for border style, and a taxonomy with three options for the various box sizes, then have my theme spit out those taxonomy terms as CSS classes (i.e. class="green coupon wide" or class="blue shoutbox tall"). Then I only need six generic boxes and the owner can use taxonomy to customize the attributes of boxes on the fly. Unfortunately, I can't see any way to categorize blocks using taxonomy. It seems you can only categorize content nodes like stories and pages.

Taxonomy is only one idea at this point. I'd greatly welcome any ideas for how I should be doing these boxes. I'll even switch away from using blocks altogether if there's a better way. The only requirement is that the owner, who has no knowledge of HTML, CSS, or the inner workings of Drupal, needs to be able to easily rearrange these boxes, choose their style, and edit their contents.

Thanks in advance for any help and ideas you can provide. Cheers!